A bout VNC, if you want to use VNC to control an internal PC througt Internet.
You have forward port 5800 and 5900, (the VNC internal PC mut have the E-smith IP adress as Gateway in the network Property) I use this
ipmasqadm portfw -a -P tcp -L [MY_INTERNET_IP_ADD] 5800 -R 192.168.1.67 5800
ipmasqadm portfw -a -P tcp -L [MY_INTERNET_IP_ADD] 5900 -R 192.168.1.67 5900
192.168.1.67 is the PC in your unternal network running VNC Server with a password.
then from an internet connected PC, i launch an internet browser with the following URL :
http://[MY_INTERNET_IP_ADD]:5800
Write your password, et voilĂ
Fred